Mount Altari, 12th century
The fortress was built during the period of the Pisan occupation as a bulwark from which to monitor the city and the surroundings. It was initially given the name of San Guantino from the ancient church perched on the hill, whereas it subsequently took the name of “Salvaterra Castle” at the behest of the Aragonese crown; the building was purchased and restructured in neo-gothic style in the nineteenth century, turning into a private residence. Today, the castle, once more partly owned by the municipal administration, houses some events and offers the visitor an unmatched view of the city.